Variable delivery vane-type hydraulic pump



Feb. 5, 1952 CRANE 2,584,426

VARIABLE DELIVERY VANE-TYPE HYDRAULIC PUMP Filed March 2, 1948 5 Sheets-Sheet 2 Ila-=5 INVENTOR. NEIL. CRANE Feb. 5, 1952 2,584,426

VARIABLE DELIVERY VANS-TYPE HYDRAULI'EC PUMP Filed March 2, 1948 5 Sheets-Sheet 3 IN VEN TOR. Nzu. CRANE Feb. 5, 1952 N,. CRANE 2,584,426

VARIABLE DELIVERY VANE-TYPE HYDRAULIC PUMP Filed March 2, 1948 5 Sheets-Sheet 4 INVENTOR. NEIL CRANE ATTORNEV Feb; 5, 1952 N. CRANE VARIABLE DELIVERY VANE-TYPE HYDRAULIC PUMP 5 Sheets-Sheet 5 Filed March 2, 1948 BBL lso

INVENTOR.

. NEIL CRANE Patented Feb. 5, 1952 VARIABLE DELIVERY VANE- TYPE HYDRAULIC PUMP Neil Crane, Detroit, Mich., assignor, by direct and mesne assignments, to Eugene A. Casaroll, Dev troit, Mich., as trustee Application March 2, 1948, Serial No. 12,604

16 Claims. (Cl. 103-1120) 1 -T-he present invention relates to a hydraulically: balanced, variable delivery, reversible vanetype hydraulic pump l A-preferred embodiment of the present invention provides a symmetrical hydraulically balancedpurnp comprising avane carrying rotor rotating between the spaced side-walls of a stationary housing and disposed to provide a pair of annular pumpingr-ecesses formed between the sides of the rotor and housing, one on each axially opposedfside of the rotor The rotor is universally mounted relative to its drive meansto permit pivoting of the rotors axis of rotation in either direction about an axis perpendicular thereto. Thus the-rotor is pivotal from a neutral position, whereat the rotor is symmetrically disposed equidistant from said spaced housing .side- Walls, to an obliqueposition, whereatdiametricallyopposed portions of the rotor are tilted towardon'e housing sidewall and away from another. e p p The vanes'lare equally spaced circumferentiallyl and mounted on the rotor for relative sliding movement transverse to the direction of rotation to permit said oblique tilting of the axis of rotation. Th vanes project from the axially opposed sides of the rotor to partition each pumping recess into a plurality of individual fluid carrying pumping chambers.

Upon rotation of the rotor about an oblique axis relative to said housing, the pumping chambers within a semi-annular inlet portion of each pumping recess gradually increase in volume and thereby develop a'low pressure intowhich hydraulic fluid flows by Way of inlet ports communicating with said inlet portions. The enteringfiuid is carried by the individual pumping chambers to a semi-annular discharg portion of each pumpin recess whereat the pumping chambers gradually decrease in volume and discharge the hydraulic fluidunder pressure by way of discharge ports communicating with said discharge portions.

By the arrangement described, each axially opposed side of the rotor serves as an active pumping element, the output oi'the pump being dependent upon the rate of change of volume Of'the pumping chambers as they rotate within the pumping recesses. vThus the output of the pump is variable or reversible merely by varying or reversing the angle of the tilt of the axis of rotation of the rotor relative to the housing, but Without otherwise changing the direction or speed of rotation. Q'I'he torque resulting from the hydrau iq 1.1. 3

let and discharge pressures exerted on the por tions of the rotor boundinglthe pumping re cesses is counterbalanced in the present invention by porting said inletand discharge pressures against portions of the rotor external to the pumping recesses, so as to hydraulically balance the rotor for torque about all axes other than the axis of rotation, thereby obviating torque between the rotor and its drive means except about the axis of rotation and permitting a ffinger-tip control over the mechanismfor varying the rotors axis of rotation and rate and direction of output. l e v Prior to the present invention, conventional variable delivery vane-type hydraulic pumps have utilized arotor'jand integral drive shaft journaled in heavy expensive, oversized bear;- ings required to com ensate for thethrust or back pressure of the hydraulic fluid on therotor. Insuch constructions, the rotor itself frequently comprised a wobble plate or eccentric member rotating so as to'vary its axis'of symmetry constantly, thereby placing additional strains on the rotor shaft bearing supports and rendering such pumps unfeasible for relatively large out puts,- 1 Another difficulty frequently encountered with the conventional variable delivery hydraulic pump employin .'slidable vanes carried by" the rotor is that centrifugal force tends to throw the vanes against stationary portions of the rotor housing, resulting in undue friction and Wear between the vanes and .Thousing, lowered opera tional efficiency of the pump, and untimely leakage of fluid by-passing the-vanes.

- Accordingly, important objects of the present inventionare:

(1) To provide a hydraulic'pump wherein the axes of rotation andsymmetry "of the rotor remain constant for uniform delivery of the pump;

and v .(2) To provide a vane-type pump having an infinitely variable delivery characteristic within the limits of the pump, whereinthe output'and direotion'of operation of thepump-may be readily varied by changing the axis of rotationxcof the rotor.

Other objects of the present invention are :to provide an improved, economically manufactured, vane-type hydraulic pump having high operating efiiciency characteristics wherein the rotor is at all times maintained in hydraulic balance regardless of: its flang-lerof rotation or the shydraulic inlet and: discharge pressures acting thereon; and. wherein the rotor is floated freely relative to its drive shaft so as to substantially eliminate torque on the drive shaft about all axes other than the axis of rotation, thereby reducing the initial and maintenance costs of the pump and permitting the use of relatively inexpensive light bearings to journal the drive shaft.

Another object of the present invention is to provide a slidable vane-type pump wherein the vanes rotating with the rotor are restrained against centrifugal force by means rotating with the rotor, thereby prolonging the operating efiiciency of the pump and avoiding a primary cause of wear which otherwise results in conventional vane-type pumps wherein the vanes are thrust by centrifugal force against stationary portions of the pump housing.

Other objects of the present invention are to provide a vane-type variable delivery hydraulic pump which iscompletely reversible in its operation; wherein the rotor may be operatively rotated in either direction; wherein the hydraulic inlet and outlet ports may be selectively reversed merely by changing the axis of rotation of the rotor, Without changing its direction of rotation; and wherein the output of the pump is readily infinitely variable between the limits of maximum output in one direction, through zero output, and maximum output in the reverse direction, merely by changing the axis of rotation of the rotor and without otherwise changing its speed or direction of rotation.

Other objects of this invention will appear in the following description and appended claims, reference being bad to the. accompanying drawings forming a part ofthis specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

Fig. 1 is essentially a vertical mid-section through the drive shaft of a hydraulic pump embodying the present invention. taken in the direction of the arrows along the line I l in Fig. 2, the rotor and integral pressure equalizing member being shown in side elevation and tilted relative to the rotor housing to show portions of the right sides thereof. r

Fig. 2 is essentially a horizontal section through the drive shaft, taken in the direction of the arrows along the line 2--2 of Fig. 1, the rotor being rotatedslightly from its position shown in Fig. 1 and the vanes being removed. Fig. 3 is a vertical section through the rotor, taken in the direction of the arrows essentially along the broken line 3-3 of Fig. 1, the rotor being shown in the central neutral position and slightly rotated from the position of Fig. 1.

Fig. 4 is a vertical section taken in the direction of thearrows along the line 4-4 of Fig. 1, the rotor being shown in the central neutral position and slightly rotated from the position of Fig. 1.

Fig. 5 is a reduced elevation of one of the forked hydraulic bearings embodying the present invention.

Fig. 6 is a reduced elevation showing the ro-' tor, together with the hydraulic bearings and pivotal yoke for controlling the axis of rotation of the rotor. The hydraulic bearings and yoke are shown partially sectioned and displaced from their assembled positions. The hydraulic bearings are shown in phantom in their assembled positions engaged with the pressure equalizing member. I

Fig. 7 is an elevation of the pivotal yoke taken from the left end of Fig. 6.

Fig. 8 is a fragmentary section taken in the direction of the arrows along the broken line 88 of Fig. 1, showing the eccentric means and pivotal yoke for pivoting the hydraulic bearings.

Fig. 9 is a fragmentary elevation taken in the direction of the arrows along the line 9-9 of Fig. 1 and showing the indexing means for selectively determining the axis of rotation of the rotor.

Fig. 10 is a diagrammatic view indicating the hydraulic pressure balance on the rotor.

Fig. 11 is a schematic section showing the system of hydraulic inlet and discharge ducts and the ducts for hydraulically balancing the rotor.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

A particular embodiment of the present invention is described by way of example in connection with the drawings. Figs. 1 and 2 show the housing 20, having the large recess 28 for the right and left rotorhousing members 30 and 32 respectively. The recess 28 is enclosed by the end cover 22 secured to the housing 20 by the plurality of bolts 24 and lock washers 26. The housin members 20, 3B, and 32 provide the coaxial shaft openings 34, 36 and 38 respectively for the rotatable drive shaft 40, its bearing supports, and the rotor.

An annular reduced portion 42 of the opening 38, concentric with the shaft 40, is provided for the shaft bearing 44 which rests against and is prevented from leftward movement, Fig. 1, by the shoulder 46 of the rotor housing member 32. The reduced left end of the shaft 40 is journaled within the bearing 44 and held against leftward movement by the annular shoulder 48 of the shaft 40, resting against the inner race of the bearing 44.

Communicating concentrically with the opening 34 is the annular recess 59 provided for the hydraulic pressure seal 52 around the shaft 40. A similar and somewhat larger concentric annular recess 58 is provided for the shaft bearing 60 which is spaced from the hydraulic seal 52 by the annular spacer 62. The reduced right end of the shaft 46 is journaled Within the bearing 50 and held in the assembled position against movement to the right, Fig. 1, by the annular shoulder 54 of the shaft 40. The bearing 60 is held within the recess 58 by the end cover 65 which is secured to the housing 20 by the plurality of bolts 16- and lock washers 12.

The Walls of the openings 36 and 38 provide the paired concentric spherical portions 14 and '16 respectively which provide bearing surfaces for the paired spherical segments of the rotor body 18. The latter is bounded between its right and left parallel sidewalls and 82 respectively, Fig. 2, perpendicular to the rotors axis. Similarly, the walls of the openings 36 and 38 provide the paired concentric spherical portions 84 and 85 having only an operating clearance from the segmental spherical surface of the annular vane holder 88, which latter is integral and coaxial with the rotor body 18. The vane holder 88 provides the plurality of equally circumferentially spaced radial slots 90 for the plurality of thin 'flat slida'ble vanes 92, which extend laterally from opposite sides of the vane holder '88 :for 'rota-tionwithin the paired annular pumping recesses 93L and 93R formed between the sidewalls of the rotor and stationary housing members on the axially opposed left and right sides respectively of the rotor.

The lateral projecting portions of each vane 92 essentially fills the cross sectional area o-fritsfportion of the pumping recesses 33L and 93R so that the latter is partitioned into a plurality of rotating pumping chambers bounded between adjacent vanes and the surfaces of the rotor and housing and adapted to carry hydraulic fluid upon rotation of the rotor. The adjacent surfaces between the vanes and the rotor and housing are accurately machined to conform to each .other so as to minimize fluid leakage from the individual pumping chambers. The outer and inner peripheral edge portions of the vanes 52 are spherical to conform respectively to the spherical surfaces 8'l8E and to the spherical surface of the rotor body '18. The lateral ends .of the vanes 92 abut the parallel annular sidewall portions 9-. and 96, which are concentric with and perpendicular to the axis of rotation of the shaft-.423 and are provided by the housing members Bil and 32 respectively. The lateral ends of the vanes 92 are also slightly convex so as to maintain .a sliding contact at all times with the said surfaces 94 and 96 regardless of the angle of rotation of the rotor.

It is to :be noted that the rotor in Figs. 2, 3 and 14 hasbeen rotated slightly from its positionof Fig. 1. In Fig. 2 the sectiondoes not pass through any of the vanes .and the pumping recesses 93L and 93R are clearly shown in section at the upper left and lower right respectively of the rotor.

The recesses within the members .30 and 32 for the spherical vane holding segment 88 are continuous with the paired annular recesses 98 and IE0, 2, provided for the pressure balancing member I92 comprising an annular disc secured coaxially to the outer periphery of the vane holder 88 for-rotation therewith. The rotor body I8, vane holding annulus .88, and pressure balancing member I92 are preferably-secured together to complete a concentric and coaxial inprovides an enlarged portion I04, Figs. 2 and 4, having the two opposed parallel faces I06 parallel to the axis of the shaft Ml. A pinhole I08 extends through the axis of the shaft and receives the pin III} which projects perpendicularly through the opposed parallel faces I 06 to receive the paired rectangular caps H2 at its opposite ends. Each cap II2 provides the recess II4 for its respective end of the pin III! and also provides the outer cylindrical surface II6, Fig. 2. The latter allows adequate clearance between the rotor and caps II2 when the axis of rotation of the rotor is at an angle to the axis of the shaft 40. The rotor body 18 provides the central axial bore I I8 of slightly larger diameter than the diameter of the-portion of the shaft 40 therein to permit tilting of the rotor body 18 relative to the shaft Ml. Driving engagement between the rotor and shaft 48 is effected by the lateral sides of the pair of diametrically opposed slots I 20, Fig. 3, extending axially of the bore IIll. Each slot I 20 is adapted to receive one of the caps 'II2 with the lateral sides of the slots I20 and adjacent sides of the caps II2 providing bearing surfaces for pivotal movement of the rotor about an axis perpendicular to the axes of both the shaft 4t and the pin I I0, and also providing a driving contact between the rotor and shaft 40.

Tilting of the axis of rotation of the rotor relative to the axis of rotation of the 'shaft 40 is effected by the coaxial, pivotaLdiametrically opposed forked hydraulic bearings I22, Figs. 1 and 5, mounted within the paired semi-cylindrical openings I24 and I26 within the rotor housing member 39 and 32 respectively for pivoting about the diametrical axis therebetween. Each bear ing I22 provides the slot I28 which receives the pressure balancing member I02, the hydraulic pressure balancing chamber I30 which extends through the bearing I22 perpendicularly to the slot I28, and the slotted cylindrical segmental bosses or prongs I32 having the channel or slot I34 between them to receive one of each of the pair of parallel arms E38 of the pivotal yoke I36, Fig. 8. The arms I38 extend along the two longitudinal recesses Mil provided therefor within the housing 29, above and below the rotor, Figs. 1, 3 and 4, and also extend into their respective slots I34 at diametrically opposed positions above and shaft I55, Figs. 2 and 8. The indexing shaft I46 is rotatably mounted at opposite ends at I4! and I49 within the cover 22 and extends upward within the recess I48 of the cover 22 and through the upper portion of the latter. An oil seal ring of the vane holder 88 to permit rotation ofthe rotor out of coaxial alignment with the shaft d2, Figs. 1 and 2, thus forming the expanding and contracting pumping chambers. As the axis of rotation of the rotoris tilted out of coaxialalignment with the. shaft 42, the vanes 92 move slidably within their slots 90 relative to the vane carrier 88 to maintain their positions for rotation within the said pumping recesses 93L and 83R essentially coaxially about the shaft 43.

Changing of the rotors axis of rotation relative to the axis of the drive shaft it is permitted by a universal coupling best shown in Figs 2, 3 and l. Within the rotor body I8, the shaft 49 I59. is provided around the shaft I within the upper journal I49.

Within the cover 22 and communicating with the recess I48 is the recess i5 3 for the cam I56 mounted eccentrically on the indexing shaft I45 and secured thereto by the pin I58 within the pinhole provided by the shaft I46 and cam I56. Rotation of the. indexing shaft I46 is effected by the knurled disc I62 secured to its upper end by the nut I64. The knurled disc I62 provides the plurality of spaced semi-circularly arranged indexing holes I66 and is selectively held in one of a plurality of indexed positions by inserting the pin Ififlthrough one of the indexing holes I66and into the pinhole no provided therefor within the upper surface of the housing 20, Figs. 1 and 9.

.It is apparent from the structure shown that as the shaft I46 and eccentric cam 85% are rotated, the latter pivotally moves the arms M4 and I38 through an are about the center of the coaxial bearings I22, Fig. 8, for pivoting the latter. The pressure balancing member I02 which rides Within the diametrically opposed hydraulic bearing slots I28 is thus pivoted about the axis of the bearings I22 to change the axis of rotation of the rotor on its aforementioned universal coupling. The position of the zero indicator H2, Fig. 9, shows the axis of rotation of the rotor tilted to the limit in one direction relative to the axis of the shaft 50. By rotating the knurled knob I62 ninety degrees clockwise in Fig. 9 the rotor wi1l be placed in the neutral or central position in coaxial alignment with the shaft 40. Upon continued clockwise rotation of the knurled disc I62 through another 90, the rotor will be tilted to the limit of its movement in the opposite direction from that shown in Figs. 1' and 2- Hydraulic fluid is supplied to and discharged from the pumping recesses 93L and 93R by four arcuate hydraulic ports, two on each axially opposed side of the rotor and extended concentri- I cally adjacent each pumping recess 93L and 93B for communicating therewith, each arcuate port being somewhat less than a semi-circle in length and being symmetrically disposed relative to the plane of the pivot axes of the bearings 522 and shaft 40. These ports are best shown in Figs. 3 and 4 and include the arcuate ports i'ML and I'MR, in hydraulic communication with each other and provided on opposite sides of the axis of rotation of the shaft within the housing members 32 and 33 respectively, and also include thearcuate ports H513 and HER, in hydraulic communication with each other and provided on opposite sides of the axis of rotation of the shaft 40 within the housing members 32 and .30 respectively. The adjacent ends of the arcuate ports I'I IL and iIfiL, Fig. 4, and correspondingly the adjacent ends of the arcuate ports IMF. and I'ISR, Fig. 3, are preferably circumferentially spaced by a distance somewhat greater than the circumferential spacing between adjacent vanes 92. Thus as each individual pumping chamber between adjacent vanes 92 is carried from one of the said arcuate ports to another by rotation of the rotor, the pumping chamber will be completely shut ofi from the one port before opening to the other port, Fig. 3. v

The ports F4L, l'I iR are in hydraulic communication with the conduits II8L and IIBR respectively, Figs. 3 and 4, which communicate with the hydraulic port I80 at the exterior of the pump. Similarly, the ports I'IBL, I'I6R are in hydraulic communication with each other by way of the ducts I82L and I82R respectively, which commun icate to the exterior of the pump at the hydraulic port I84.

Assuming for the sake of illustration that the rotor is tilted as shown in Figs. 1 and 2 and that the shaft 40 is rotating in the direction of the arrow I86, 1. e., clockwise as seen from the right end in Fig. 2, the rotation of the rotor will be clockwise similarly, but around an axis at an angle I8! to the axis of rotation of the shaft 40. In this situation, the individual pumping chambers between adjacent vanes 92 in the upper portion of the pumping recess 93L and the lower portion of the pumping recess 93R, i. e., in communication with the arcuate ports I'I4L and I'I IR, gradually pressure balancing member I02.

. 8 increase in volume from minimum to maximum as they pass over the said ports I'I IL and I'I4R, creating a suction in these pumping chambers toward which the inlet hydraulic fluid flows from the port I by Way of the conduits [18L and I'I8R.

Similarly, the individual pumping chambers between adjacent vanes 92 in the lower portion of the pumping recess 93L and the upper portion of the pumping recess 93R, i. e., in communication with the arcuate ports II6L and IIBR, gradually decrease in volume from maximum to minimum as they pass over the said ports I'I6L and HER. The fluid is thus forced out of these pumping chambers and through the port I84 by way of the conduits I82L and I82R.

Accordingly, with the rotor tilted as shown in Figs. 1 and 2, the upper portion of the pumping recesses 93L and the lower portion of the pump,-

ing recess 93R, the arcuate ports I'ML and IMR,

the conduits 'I'I8L and IIBR, and the port I80, all

in communication with each other, become the complete hydraulic inlet portion of the pump. The lower portion of the pumping recess 93L and the upper portion of the pumping recess 03R, the ports I'ItL and IlfiR, the conduits I82L and I82R, and the port I84, all in hydraulic communication with each other, become the complete discharge portions of the pump. It is apparent from the structure shown that the hydraulic ports I80 and H84 may be interchangeably the inlet or outlet ports, depending upon the direction in which the axis of rotation of the rotor is pivoted relative to the axis of the shaft 40. It is not necessary to reverse the direction of rotation in order to reverse the direction of operation of the pump. Likewise, it is apparent that the volume output of the pump depends upon the rate of change of the volume of the individual pumping chambers as they rotate within the pumping recesses 93L and 93R, which in turn depends upon the angle I31 between the axes of rotation of the rotor and shaft 40.

The relatively low hydraulic pressure Within the inlet portions of the pumping recesses 93L and 93R and the relatively high hydraulic pressure Within the discharge portions of the pumping recesses 33L and 93R exert a torque on the rotor tending to rotate the latter about a, horizontal axis perpendicular to its axis of rotation. For example, with the rotor tilted as shown and rotating in the aforesaid clockwise direction, the hydraulic pressure within the discharge portions of the pumping recesses 93L and 03B tends to force the lower portion of the rotor to the right and the upper portion of the rotor to the left, Fig. 1. Torque of comparatively smaller magnitude is also exerted on the rotor as a result of the pressure within the inlet portions of the pumping recesses 93L and 93R.

The above mentioned torques exerted on the rotor during normal operation arecounterbal anced in the present invention by means of the diametrically opposed pressure balancing chain,- bers I30 within the forked bearings I22, each communicating with axially opposed sides of the The conduits I88L and I88R, communicating with the ducts IISL and II8R respectively, conduct fluid to the pressure balancing chambers I30 at the lower left and upper right sides of the member I02 respectively. Similarly, the ducts I001. and IO0R, communicating with the ducts IB2L and I82R respectively, conduct fluid to the pressure balancing chambers I30 at the upper left and lower right sides respectively of the member I02, Fig. 1. Thus the arcuate ports I'I4L, I'I IR and the portions of the pressure at the lower left and upper right of the disc I92 are in hydraulic communication with each other and atthe-same hydraulic pressure. Similarly, the arcuate ports IIBL, Il-GR and. the portions of the pressureequalizing chambers I30 at the lower right andupper left of the disc m2 are hydraulic communication with each other and at the same hydraulic pressure.

The areas of the pressure balancing chambers I30 which open to the opposite sides of the member I02 are selected in consideration of their distances from the center of the rotor so as to completely balance the torque on the rotor resulting from the hydraulic pressures within the pumping recesses 93L and 93R, The balancing of the pressures on the rotor is indicated in 10, which may be considered a schematic vertical.

section perpendicular to the axis of rotation of the shaft 40. The port HGL and the portion of the chamber I30 opening to the left side of the disc I02 are shown in solid lines. The port IZER and the portion of the chamber I39- opening to the right side of the disc I02 are shown in dotted lines. I92L and IQZR represent the centers of gravity of the areas A192L and A1923 respectively (indicated in the mathematical expressions below) within the pumping recesses 93L and 93R respectively and in contact with the surface components of the rotor which are perpendicular to its axis of rotation and also in communication with the ports I'ISL and IltR respectively. The torque T resulting from hydraulic pressure acting on the said areas Aim andAisza for which I92L and I92R respectively represent the centers of gravity, and tending to rotate the rotor about a horizontal axis perpendicular to its axis of rotation, is given by the expression:

wherein P is the pressure on the areas A192L and A192R; and 131941.. and D194R are the distances i341 and I94R respectively of the centers. of gravity I92L and ISZR respectively from the axis of rotation of the rotor. By the symmetry of construction, A192L=A192R, and D194L=D194R. Obvious- 1y, PA192LD194L is the torque tending to force the lower portion of the rotor to the right in Fig. 1. PAl92RDl94R is the torque tending to force the upper portion of the rotor to the left in Fig. l.

The points IQGR and I96L represent 7 the centers of gravity of the areas of the right side of the lower pressure balancing chamber Itiland the left side of the upper pressure balancing chamber I30 in contact with the member H32.

The size and disposition of the chambers i3?! are determined so that the following equalities exist: A196RD198R=A192LD194L and r wherein Amen and A196L are the areas for which the points I96R and I95L respectively are the centers of gravity; and DIQBR and Drier are the distances I983 and I98L respectively. Also by the symmetry of construction,

recesses 93L andQSRr and directed against the equalizing chambers I3t:

upper rightiand lower its; sides. of; the: rotor to. rotate-the latter about. a: horizontal axisperpendicular' to its: axis, of rotation; is.- counterbalanced- Similarly, the torque on the rotor about the:-

horizontal axisperpendicular to its axis of, rotation: and; resultingv from, hydraulic pressurewithin the upper andulower portions-respectively of the pumping recesses, and 93B; and in lay-'- dr'auli'cl communication with the arcuate ports.

H 41, and Il -i3 is; counterbalanced bycommuni ters of gravity HZ'L [92R and ISEL', I963 all lie on a diameter iparallelto the: said vertical Thus: every moment of. force on one side of the vertical axis is counterbalanced by a corresponding. moment of force on the other side thereof. 1 l V I I Itis-also to be noted: that the hydraulic balancing of axiallyopposedrportions of: the 'rQEQI' efiected mthepresent; invention y he pressure balancing chambersgiim within the forked.- bearings, 122,-, provides asimple and efiioient by draulic bearing action for the saidiorked bearings 122-, which. guides the: rotation, of the rotorabout an axis at a selected angle relative to the axis of the drive shaft 40. f r r i In order to relieve hydraulic; pressure which may occasionally-develop within various portions of the: pump housing-as a result'ofleakage outside of the operating chambers or ducts of the pump; Pressure relief ducts 200 and 2:02 within thehousing ztt communicate with the ports left and; I84 respectivelyr Fig, 2r,-andi with, the

, pressure relief valve chambers 2,04 and. i103 re,-

spectively, which in turnv communicate respectively, with the ducts 208 210; within, the,

housing, 20 Ball valves 2 I2; and ,2 .I14-;within the chambers 20Itand 2 06,respectivel;y; are seated against the; openings to the-ducts 208 and 21 0- of the housing members 20 and, 30, communicate with'theducts 208: and 2H1 respectively and with the right, side of the chamber Qt-I00 within which, the rotor member I;02y-rotates. The left side or the chamber .98-I00acommunicates with the chamber I48 by way of the ducts 228 and 230 within the rotor housing member 32. I The[endsoi the ducts llliiand 20 2 removed from the ports I and Boare suitablyv plugged by the respective screw-threaded tapered plugs 240 and 242. Similarly, screw-threaded tapered plugs 236 and 238 are; provided, to close. the. exterior ends of thevalve chambers 204 and 200 respectively. By suitably adjusting the tension in the springs 220 and 222, the pressureat which the ball valves 212 and 2I4 open tofdischarg e M2 and 2I4 serve as one way check valves ,to

operation of the pump of the-present invention is readily apparent. We may assume the rotation of the shaft 40 to be clockwise as indicated in Figs. 1 and 2, although the pump is completely reversible in every sense and performs equally well regardless of the direction of rotation of the shaft 40. Upon rotation of the knurled knob I62 in one direction or the other, as for example to the positionshown in the drawings, the eccentric cam I56 keyed to the shaft I46 pivots the arms I44 of the yoke I36 about the pivot axis of the rotatable hydraulic bearings I22 and thereby tilts the'axis of rotation of the rotor about the vertical axis of the bearings I22 by virtueof the-forked engagement between the sides of the slots I 28 and the rotor member I02.

-The operation of the pump may be readily followed by reference to the schematic plan of the hydraulic system, Fig. '11, wherein the rotor is shown in the neutral position in coaxial alignment with the shaft 40.- In this position, no pressures are developed by the pump and. the output is zero. With the rotor tilted as shown in Figs. land 2, the ports I80 and I84 become the hydraulic inlet and discharge ports respectively. The ducts II8L and "SR, the arcuate ports Il4L and I'I4R, and the pressure equalizing ducts I8BL and I88R, are all in hydraulic communication and become the complete inlet body of hydraulic fluid at the inlet fluid pressure. The complete discharge body of hydraulic fluid at the hydraulic discharge pressure is contained within the port I84, theconduits I82L and I82R, the arcuate ports I'IBL and IIBR, and the pressure equalizing-ducts I90L and I90R.

Considering firstthe action within the pumping' recess 93R upon the aforesaid clockwise rotation of the rotor, hydraulic fluid enters the individual pumping chambers which are exposed to the arcuate port II4R, Fig.1. As each individual pumping chamber on the right side of the rotoris carriedacrossthe port I'I4R, the said pumping chamber gradually increases in volume and creates a partial vacuum therein toward which hydraulic fluid flows from the arcuate port I-I4R, duct I'I8R,and inlet port I80. Upon continuedrotation,-the pumping chambers carry the entrapped fluid into the upper or discharge portion of the pumping recess 93R and across the arcuate port IIBR. As the pumping chambers gradually rotate across the port-IIGR, they gradually decrease in volume and force the hydraulic fluid therein through the port I'IBR and out the discharge port I84-via the duct I82R. In-a like mannenhydraulic fluid is conducted from the inlet port' l80 to the pumping chambers on the left side of the rotor via the arcuate port I'I4L and is discharged through the arcuate port I'IEL to the discharge 'port- I84."

As may be readily observed in Fig. 11, assumingthe rotor to be tilted as shown in Figs. 1 and 2; the inlet' pr'essure-on the lower right side of the rotor in communication-with the arcuate inlet port I 14R is counterbalanced by the inlet pressure delivered to 'the lower pressure balanci'ng chamber I on the left side of the member I02 via the duct 'IBBL. The inlet pressure on the upper'left side ofthe rotor in communication with the arcuate inlet port I'I4L- is counterbalanced by the inlet pressure communicated'tothe 12 upper pressure balancing chamber I 30 'onth'e' right side of the member I02 via the duct IBBR. The hydraulic discharge pressure on the lower left side of the rotor in communication with the arcuate discharge port I'IGL is counterbalanced by the discharge pressure conducted to the lower pressure balancing chamber I30 on the right side of themember I02 by way of the duct ISIJR. The discharge pressure on the upper right side of the rotor in communication with the arcuate port HER is counterbalanced by the discharge pressure conducted to the upper pressure balancing chamber I30 on the left side of the member I02 via the duct I90L. Thus the rotor is maintained in hydraulic balance regardless of the angle of its axis of rotation. Thrust between the rotor member I02 and the forked bearings I22 is essentially eliminated and pivoting of the axis of rotation of the rotor is permitted without appreciable effort. The output of the pump is thereby readily varied or reversed in direction Without appreciable strain on the pump mechanism, except for changes in the driving torque. Since the rotor is floated freely relative to the drive shaft 40, the only appreciable torque on shaft 40 is about its axis of rotation. Accordingly, the use of relatively small bearings '44 and is permitted for journaling the shaft 40, increasing both the operating economy and emciency of the pump.

The angle between the axis of rotation of the rotor and the shaft 40 determines the rate of volume variation of the pumping chambers upon rotation of the rotor and thereby determines the output of the pump. The pump will accordingly be at its maximum output in one direction or the other when tilted in either direction to the maximum allowable tilt, and will have zero output when the rotor is in coaxial alignment with the shaft 40. Thus there is provided a balanced, infinitely variable vane-type pump, which is reversible as to inlet and discharge ports without changing the direction of rotation of the drive shaft 40. Inasmuch as the rotor rotates about a strains, which are ordinarily set up in the Wobble-plate type of pump or the type of pump wherein the rotor is an integral part of the drive shaft, are avoided in the present invention.

Although the vanes 92 are slidable within their slots 90,'they are restrained by the inner periphery of the member I02 from radial movement resulting from centrifugal force. Thus friction contact and wear between the vanes 92 and the stationary surfaces of the housing resulting from centrifugal force is avoided. It follows as a corollary that leakage of hydraulic fluid around the vanes within the pumping recesses 93L and 93R, as a result of wear, is also minimized, assuring optimum operating efficiency throughout prolonged use.

By the above disclosure, novel and important with a minimum of wear between the rotating vanes and stationary parts of the pump, whereby simplified and improved hydraulic means are provided for tilting and maintaining the axis of the rotor in a pre selected position, and whereby the hydraulic pressures exerted on bearing assures the rotor during-normal operation are hydrauln orally-counterbalanced. 1

Iclaim: I

1; In a rotor type pump including a rotor having an operative pumping portion and exter nal portion and also including a rotor housing, a pumping recess in said rotor housing, the pumping portion of the rotor being rotatable within said pumping recess, means to counterbalance forces on said'rotor and including means to conduct pressure from said recess against portions of said rotor external to said recess, said external portions being spaced-- radially outwardly from the axisof rotation of said rotor and also being spaced radially outwardly from. said pumping portion.

2; In a pump having a rotor operatively mounted for changing the axis of rotation thereof relative to stationary portions of said pump, said rotor having-- annular portions, means to change said axis of rotation and including pivotally mounted forked bearin'g'means having the annular portions of said rotor disposed between and slidable within the fork prongs.

3'. In a pump having a pumping recess formed between a stationary housing anda roto'n the latter being mounted for changing its axisot rotation, the combination of a forked hydraulic bearing means pivotally mounted within said housing and havingportions' of the" rotor disposed between thefork prongs and adapted to engage the-same for pivoting the axis of rotation of said rotor, said hydraulic bearing-means including a hydraulic pressure balancing chamber in hydraulic communication with the pressure of said pumpingrecess and opening against portions of said rotor. a a

4. In a variable delivery vane-type hydraulic pump having a stationary housing and a rotor, the combination of a pumping recess having spaced sidewalls 7 comprising portions of said housing and said rotor, hydraulic i-nl'etand. dis charge ports communicating with separate portions of said pumping recess, means. to. car.ry fluid from one portion of said pumping recess to. another and including a plurality of vanes extending outwardly from and carried. bysaiol rotor for rotation therewith Within. said pumping recess and adapted for partitioning the latter into a plurality of rotating pumping chambers, said rotor beinguniversally mounted for pivoting its; axis'of rotation-so that the volume'of said pumping chambers becomes progressively larger upon rotation within the portions of. said pumping recess in communication with said inlet port and becomes progressively smaller upon rotation within the portions of said pumping recess in communication with said discharge port, said vane being movably mounted on said voter to conform to variations. in theispacing between the sidewalls of said housing and said rotor eiiected by pivoting of the axis of rotation of said rotor, means for selectively controlling said pivoting of the axis of rotation, and means"ex ternal to said pumping recess to counterbalance operational pressures therein directed against said rotor and including inlet and discharge pressure balancing chambers in hydraulic communication with said inlet and discharge ports respectively and opening against portions of said rotor in opposition to the said operational pressures within said pumping recess. l

5. The combination as claimed in claim 4 and being further characterized in that said rotor provides a peripheral pressure balancing memi4 ber secured thereto in cor1"c'entricitywith the axis of rotation thereof, and inthat said inlet and discharge pressure balancing chambers open against saidipressurebalancing member;

5 6. The combination acclaimed in claim 5 and being further characterised in that said means for controllingthe pivoting of said rotors axis of rotation include apair t diametrically op-L posed forked hydraulic bearings, the fork prongs is of each bearing being engaged with opposed sideso-f said-- pressure balancing member for pivotin-g thereot upon the. pivoting of said forked bearings, and in. that said inlet and. dischargepressure balancing chambers. are provided withinsaidf'orks. I

The. combination as. claimed. inclaim 4. and being. further characterized. in. that. said means for controlling. the pivoting of said rotors axis of. rotation include a pair of diametrically op- 39 posed pivotally mounted forked bearings having portions of said rotor disposed between andengaging the fork prongs thereof, and; in that thev said. inlet and discharge. pressure balancing chambers are provided within said prongs- 8.: In a variable delivery vane-type hydraulicpump, the combination of a stationary housing, a rotor within said housing, an annular pump ing recess oneach of. the axially Opposed sides or said rotor, each recess having, spaced side walls ccmprising portions of said housing and;

said. rotor, said housing and said rotor being. operatively mounted for tilting. relative to each other to. provide inlet and; discharge portions -within each of said pumping recesses wherein the volume per unit circumferential. distance taken in the direction of rotation of said rotor becomes progressively larger throughout; each inlet portion and becomes progressively smaller throughout each discharge portion, hydraulic 4'53 inlet and outlet conduits communicating with each pumping recess at the inlet portions and. outlet portions. thereof. respectively, vane means carried by said rotor for moving fluid within said pumping recesses from the inlet portions thereof tothe discharge portions. thereof, means for controlling the said relative tilting between:

saidhousing and rotor so as to selectively vary the progressive circumferential. volume variation. within said pumping recessespsaid' rotor also having portions. extending externally of the recesses, and means to counterbalance operational forces. on said. rotor and; including. pressure. balancing chamber means. in hydraulic pressure. communication with said pumping recesses and opening against. portions of. said rotor external. to said recesses and in opposition to said forces. 9.. The combination as claimed.v in. claim v8 and. being further characterized in that said pressure balancing clzlamberv means. include a. pair. of

discharge. pressure. balancing chambers, one of each. being, disposed to counterbalance. torque on said. rotor perpendicular to its. axis of rotation and; resulting from the pressure within the discharge portions. of. one. of' each of the said two pumping recesses, and a. pair of. inlet. pressure balancing chambers, one of each being disposed to counterbalance torque on said rotor perpendicular to its axis of rotation and resulting from the pressure within the inlet portions of one of 7 each of said two pumping recesses.

10. The combination as claimed in claim 8 and being further characterized in that said means for controlling the relative tilting between said housing and said rotor include a pair of diametrically opposed pivotally mounted 15 forked bearings havin the fork prongs engaged with said rotor for pivoting thereof.

11. The combination as claimed in claim and being further characterized in that said diametrically opposed pivotally mounted forked bearings are pivotal about the diametrical axis therebetween, each of said forked bearings provides a pair of spaced forked prongs extending radially inward to engage axially opposed sides of said rotor for pivoting the latter about said diametrical axis, said pressure balancing chamber means include four pressure balancing chambers, one pressure balancing chamber being provided by each of the said four prongs engaged with said rotor, two of said pressure balancing chambers are in hydraulic pressure communication with the discharge pressure of said pumping recesses, the other two of said pressure balancing chambers are in hydraulic pressure communication with the inlet pressure of said pumping recesses.

12. The combination as claimed in claim 8 and being further characterized in that said rotor provides a peripheral pressure balancing member secured thereto in concentricity with the axis of rotation thereof, and in that said pressure balancing chamber means open against portions of said pressure balancing member.

13. In a variable delivery vane-type hydraulic pump, the combination of a rotor housing having internal sides, a rotor rotatable within said housing and having axially opposed sides, a pair of pumping recesses formed between the axially opposed sides of said rotor and the sides of said rotor housing, a plurality of spaced vanes carried by said rotor for rotation within said pumping recesses and extending transverse to the direction of rotation to partition each of said pumping recesses into a plurality of pumping chambers, said vanes being mounted on said rotor for relative slidable movement transverse to its direction of rotation, a drive means for said rotor, a universal coupling between said drive means and rotor to permit changing of the axis of rotation of said rotor so that said pumping chambers gradually decrease in volume while rotating within one portion of each of said pumping recesses and gradually increase in volume while rotating within another portion of each of said pumping recesses, means for selectively changing the axis of rotation of said rotor, hydraulic inlet and discharge conduits communicating with each of said pumping recesses at the portionsthereof whereas the pumping chambers increase in size and decrease in size respectively, a peripherally disposed pressure balancing member secured to said rotor concentrically with its axis of rotation, a plurality of pressure balancing chambers, each chamber being in hydraulic communication with either the discharge pressure or the inlet pressure of said pumping recesses and opening against selected portions of said pressure balancing member to counterbalance said rotor against the corresponding inlet or discharge pressure exerted on said rotor within said pumping recesses.

14. The combination as claimed in claim 13 and being further characterized in that said means for changing the axis of rotationof said rotor include a pair of diametrically opposed pivotally mounted forked bearings pivotal about the diametrical axis therebetween, each of said forked bearings having a pair of spaced forked prongs extending radially inward to engage axially opposed sides of said pressure balancing member for pivoting said rotor about said diametrical axis, one of each of said pressure balancing chambers being provided by one of each of the said prongs engaged with said pressure balancing member.

15. The combination as claimed in claim 14 and being further characterized in that the inner periphery of said peripherally disposed pressure balancin member engages portions of the outer periphery of each of said vanes to resist the centrifugal force of said vanes.

16. In a variable delivery vane-type hydraulic pump, the combination of a stationary housing, a rotor mounted within said housing for selectively pivoting its axis of rotation, a pumping recess formed between said rotor and said housing, means to carry fluid from one portion of said pumping recess to another and including a plurality of vanes carried by said rotor for rotation therewith, and mounted thereon for partitioning said pumpingrecess into a plurality of rotating pumping chambers, said vanes being movably mounted on said rotor to permit said selective pivoting of its axis of rotation so that said pumping chambers gradually decrease in volume while rotating within one portion of said pumping recess and gradually increase in volume while rotatin within another portion of said pumping recess, an inlet port opening into the portion of said pumping recess Whereat said pumping chambers increase in volume, an outlet port opening from the portion of said pumping recess whereat said pumping chambers decrease in volume, and means to control the said selective pivoting of the rotors axis of rotation, said means for controllng the selective pivoting of the axis of rotation of said rotor including a pivotally mounted forked bearing having the forked prongs engaged with opposite portions of said rotor for pivoting the latter upon selective pivoting of said forked bearing.

- NEIL CRANE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,777,923 Johansson Oct. 7, 1930 2,017,825 Woodford Oct. 15, 1935 2,353,780 Neuland July 18, 1944 FOREIGN PATENTS Number Country 7 Date 426,928 Great Britain Apr. 11, 1935 444,970 Great Britain Apr. 1, 1936 485,660 Great Britain May 24, 1938 626,506 Germany Feb. 27, 1936 

